Carcinoid Syndrome

The carcinoid syndrome is a collection of symptoms and signs associated with the production of chemicals and hormones produced by a very rare cancer. The cancer is called Carcinoid and the most common chemical produced is called serotonin and it can cause patients to have hot flashes, sweating, rapid heart beat, wheezing and diarrhea. These episodes can be transient or prolonged and tend to be repetitive, convincing the patients that something is wrong. It is these symptoms that bring this cancer to the attention of patients. It occurs because, distributed throughout the body, are a group of specialized cells called neuro-endocrine cells. The cells are normally present, in small collections, in the lungs and in the gastrointestinal tract. Their function is to produce small amounts of hormones and chemicals to modify and refine the normal physiological function of these two organs. What causes them to grow and become malignant is not known but when they do, they can produce copious amounts of unneeded chemical and hormones which produce the carcinoid syndrome. These rare cancers occur in the lung, the small intestine, the appendix and the rectum most commonly. Since serotonin is the commonest chemical they produce, hot flashes, rapid heart beat, wheezing and diarrhea are frequent complications of having the cancer. But they can also produce other hormones that effect the production of steroids, parathyroid and thyroid hormones, diarrhea causing proteins, insulin and glucagon. If the cancer is localized at the time it is diagnosed, it can be cured by resection of either the lung or the small intestine. If it has already spread from its primary site, then all physicians can do, is to control its side effects. The diagnosis is made by doing a biopsy of the suspected mass and measuring the amount of serotonin it is producing. As this cancer commonly spreads to the liver, a CAT scan of the liver should be done and a 24 hr collection of urine should be assayed for the metabolite 5-HIAA, the break-down product of serotonin. Once it is determined that the cancer has spread from its primary site, physicians only try to control the symptoms the cancer is causing because Carcinoids are very slow growing and patients can live with them for a long time before they threaten life. A drug called Octreotide is frequently useful in controlling the diarrhea caused by the carcinoid syndrome. This drug has to be given subcutaineously every eight hours by the patients so treatment is difficult. More long acting analogues of Octreotide will be available soon and this will help to make treatment easier. Some patients with this disease get right heart trouble because the tricuspid valve of the heart is narrowed by serotonin, leading the patients to have shortness of breath. This is a rare complication of the syndrome and only experienced cardiologists should manage this problem. Hepatic Metastases. This is a life threatening complication and must be carefully followed. Initially only the side effects of the serotonin are treated, but as the quantity of the cancer in the liver increases, then chemoembolization is initiated. This is a treatment where specific chemotherapeutic drugs, name Adriamycin and Platinum are injected directly into the liver to decrease the tumor mass and control its growth. Carcinoid is a very vascular tumor so responds well to this treatment and the decreased production of serotonin and other hormones will often alleviate the diarrhea. When the cancer spreads to other parts of the body, to bone, lung or brain, then localized treatments are used. The brain metastases can be treated with localized radiation therapy, either with the Gamma-Knife or the Accurray. Metastases to bone can be treated with regular radiation therapy. When the cancer becomes more aggressive, then systemic therapy is used to control the cancer. Currently Interferon and Octreotide are used initially and this works in about forty percent of the time. Streptozotocin, Cis-Platinum, Etoposide and Adriamycin have all been used with some success, either singly or in combination. This is a rare cancer and only physicians who are familiar should treat the disease. The object of treatment is to keep the patient as free of symptoms as possible and to prolong life. For the patients, managing the diarrhea is a continuous problem and each one learns how to control their own. Usually proteins and sugars and fats are easily absorbed and do not exacerbate the diarrhea; some vegetables are very irritating and make the diarrhea worse. Carrots and peas are acceptable but broccoli, cabbages, Brussel-sprouts, beans and lettuces are bad. Patients need to avoid whatever makes the diarrhea worse. Patients with copious diarrhea need to be careful not to become dehydrated or low in essential elements like potassium, magnesium, iron or the various vitamins. It is essential do daily weights and to always notice the color of the urine. A dark brown or deep yellow urine usually means dehydration and sometimes fluid has to be given intravenously to keep up with the fluids lost in the diarrhea. Replacing the essential elements and daily vitamins are essential. The other clinical problems associated with the carcinoid syndrome, that of a rapid heart beat and wheezing of the lungs may need to be managed by a cardiologist and a pulmonologist. The hot flashes can be treated with either Benadryl if mild and clonidine hydrochloride if severe. Most patients learn to live with them. Though cure is desirable, it is currently not possible with the treatments modalities we have available to us to-day but hopefully success in not too far away.